diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index daae2244..1d475fb0 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -34,7 +34,7 @@ jobs:
     #     ocaml-compiler: ocaml-system.4.09.1 # must match nix develop's ocaml version!
     # - run: opam install . --deps-only --with-test
 
-    - run: dune build
+    - run: dune build --profile release
     - run: ./coverage.sh test
       id: coverage